This product works well with L-Methylfolate (5-MTHF). For those with homozygous MTHFR 677C-T mutation Norival and L-Methylfolate 10mg has helped my mental clarity, lethargy, moodiness, and depressive episodes. I am not on any antidepressants. Has also worked well for my teenage son with the same double MTHFR mutation.

Restless leg syndrome is a dopamine deficiency like Parkinson ’s disease or Attention Deficit Disorder. Tyrosine is the amino acid necessary for dopamine production. Tyrosine requires B-12, folinic (folic) acid and B-6. Many of us do not properly metabolize standard folic acid, requiring an alternative form called Biopterine (BH4). Plain tyrosine gave me terrible diarrhea, even when taken with B-complex. This is the only tyrosine combination I can take without negative side effects. Taken 2 hrs before bedtime helps with the restless leg insomnia, or when I get the shakes, or early in the morning when I just can’t get going, really works. Love this product!

I've just discovered I have a rare inborn error of metabolism that leads to low levels of tetrahydrobiopterin (BH4). I tried ordinary L-tyrosine and it worked. Norival actually includes biopterin (although doesn't state which form BH4 or BH2)and cofactor P5P, in addition to N-acetyl L-tyrosine (active form). A deficiency of an enzyme is felt in every cell, especially in the brain. Norival made my brain work properly, my temperature regulation improved amazingly! The dose must be individually adjusted. I take all such supplements 3x daily, in smaller doses, to keep the blood supply stable. I only wish I could contact the company, to learn which biopterin they use.

Tyrosine helps with the production of dopamine which is lacking in people with Parkinson's. Some people like myself have a hard time assimilating tyrosine without it's co-factor biopterin. Norival has both N Acetyl L Tyrosine and Biopterin. It has been of great help in reducing my symptoms.